<html>
<title>登录</title>
<body>

<div>
    <form action="/login" method="post">
        <span>用户名:</span><input name="username" type="text" placeholder="请输入用户名">
        <span>密码:</span><input name="password" type="password" placeholder="请输入密码">
        <button type="submit">登录</button>
    </form>
    ${msg!}
</div>
</body>
</html>